1. Field of the Invention
The present invention relates to processes for purifying isoprene produced by catalytic decomposition of dimethyldioxane from carbonyl compounds and cyclopentadiene. The isoprene thus purified is used as a monomer in the production of stereospecific isoprene rubber.
2. Description of the Prior Art
Known in the art is a process for purification of isoprene produced by catalytic decomposition of dimethyldioxane from carbonyl compounds and cyclopentadiene by close fractionation on at least 50 theoretical plates of at least 50 and at a reflux ratio of at least 3, followed by washing the resulting isoprene with water. The residual content of carbonyl compounds and cyclopentadiene in the purified isoprene produced by this process is 0.0005 and 0.0005-0.0004 wt.% respectively. A disadvantage of this process is the relatively high residual content of micro-impurities (carbonyl compounds and cyclopentadiene) in the purified isoprene, which, in turn, results in an impaired quality of isoprene rubber and increased Ziegler catalyst consumption during the subsequent polymerization of the isoprene.